A simple statement from Appendix 1 of the USDA/FSIS’s HACCP regulation summarizes why cleaning and sanitizing is so important to food processors:
Sanitation maintains or restores a state of cleanliness, and promotes hygiene for prevention of foodborne illness.
Sanitation is perhaps the most detailed and complex of the prerequisite programs that form the foundation for producing safe foods. And, depending upon the products and processes, sanitation may be deemed a preventive control under the Preventive Controls for Human Food Regulation found in 21 CFR Part 117 or an Operational Prerequisite Program (oPRP) for processors who are ISO 22000 certified or operating under the FSCC 22000 audit scheme. This means that the company in question has determined that cleaning and sanitizing are essential for ensuring food safety.
Cleaning and sanitation are, however, far more than just chemicals used for cleaning. In fact, the different elements that make up a program can be summarized using the acronym TACT WINS which may be seen in sidebar 1.
And, it is even more than these eight elements. A company’s cleaning program starts with the equipment and physical plant. Making a commitment to the basic principles of sanitary design must be part of the equation. These ten principles may be seen in Figure 1. The first principle, “Cleanable to a microbiological level” summarizes the ultimate goal and mirrors the statement that led off this article. Purchasing equipment that meet these criteria is the first step towards ensuring that the cleaning can be done properly and fairly easily, especially when one looks at the 3rd principle “Accessible for maintenance, inspection, cleaning and sanitizing.”
Principles of Sanitary Design
- Cleanable to a Microbiological Level
- Made of Compatible Materials
- Accessible for Inspection, Maintenance, Cleaning & Sanitation
- No Product or Liquid Collection
- Hollow areas Hermetically Sealed
- No Niches
- Sanitary Operational Performance
- Hygienic Design of Maintenance Enclosures
- Hygienic Compatibility with Other Plant Systems
- Validate Cleaning & Sanitizing Protocols
One of the basic tenets of food plant operations is the simpler the task, the greater the probability it will not only be done, but be done properly. So, if it is easy to clean a piece of equipment, there is a greater chance that it will be done properly. Think about it. If a person has to use a special tool to loosen and remove several screws to access a unit to clean it, it may not be done right. On the other hand, if the individual simply has to pop two or three quick releases to access the unit, the chances are higher that the work will be done properly.
Developing a sanitation program
Let’s take a look at the basic tools needed when developing a cleaning and sanitizing program. Look at the elements making up TACT WINS which, incidentally, are not eight independent elements but eight integrated issues. We need the following:
- Cleaning chemicals
- Sanitizing chemicals
- Tools—Brushes, cleaning systems or other similar tools
Let’s look at each of these pieces of the pie.
Water: Water is the universal solvent and plays a role throughout the different steps making up the process of cleaning and sanitizing a piece of equipment or some part of the food plant itself. Water is employed in the first step of almost every cleaning operation. It is used to remove gross soil from equipment surfaces or elsewhere. The food industry has learned that high volume, low pressure flow should be used in these and other steps so as not to aerosolize potential contaminants. To save water cleaning floors, many operators resort to squeegees to move the gross soil such as food waste.
Water is also used as a cleaning fluid for certain types of soil such as sugar as may be seen in Table 2. Equipment used to manufacture products such as carbonated soft drinks or juices may be cleaned by flushing with hot water but in practice a mild alkaline cleaner is usually employed. However, if the product is heated, there is always a potential for burn-on so a stronger cleaning compound of some sort should be used.
Now, all water is not the same. When setting up a cleaning program it is imperative that the processor understand the chemistry of all the water systems used in the facility, whether they may be mixed with cleaners and sanitizers or not. This should be one of the first questions asked by the chemical suppler. In fact, they should collect water samples themselves and run their own tests. The first key element is water hardness, that is, the level of calcium carbonate in the water. The second key element is to know the pH of the water (Table 1). A cleaning chemical designed for use in soft water very often will create another problem if used in hard water, that is, the re-deposit of minerals and soils on the surface of the equipment being cleaned. In other words, the surface of the cleaned equipment may be covered with a white, soily mineral film commonly referred to as “RE_DEP.”
|Soft||0 - 60||0 - 3.5|
|Moderately hard||60 - 120||3.5 - 7.0|
|Hard||120 - 180||7.0 - 10.5|
|Very hard||> 180||> 10.5|
|gpg - Grains per Gallon 17.2 ppm CaCO3 = 1 gpg|
Cleaning Chemicals: As noted above, water may be used for cleaning depending upon the type of soil. However, most companies rely on one or more different chemicals to clean their plant. And, one must remember the old adage: “You cannot sanitize a dirty surface.” This statement lies at the heart of all cleaning programs.
Statistics indicate that 95% of all microbiological problems that occur in food processing facilities can be traced to a failure to clean not a failure of the sanitizer. Far too many food processors believe that the santizer is the “magic bullet” that will solve all their problems. Wrong.
Your supplier of cleaning chemicals should primarily focus on helping get the cleaning protocols correct, not which sanitizer to use. An example of the importance of cleaning is what must be done if a processor has biofilm concerns. The biofilm must be removed through proper cleaning which will entail the use of chemicals and probably some form of scrubbing. Lechavalier et al back in 1988 reported that attached cells were 150 to 3,000 times more resistant to hypochlorous acid than unattached cells; so, get it clean prior to using the sanitizer.
|Food (Or Soil)||Solubility Characteristics||Cleaning Procedure Recommended|
|Sugars, organic acids, salt||Water Soluble||Mildly alkaline detergent|
|High protein foods (Meat, poultry fish)||Water soluble
Slightly acid soluble
|Chlorinated alkaline detergent|
|Fatty foods (fat meat, butter, margarine oils)||Water insoluble
|Mild alkaline detergent. If ineffective, use strong alkali|
|Stone-forming foods, mineral scale (Milk products, beer, spinach)||Water soluble
|Chlorinated cleaner or mildly alkaline cleaner; alternate with acid every 5th day|
|Hear precipitated water hardness||Water soluble
|Starchy foods, tomatoes, fruits, vegetables||Partly water soluble
|Mildly alkaline detergents|
So, it is imperative that a processor select not only the right cleaning compound, but the means to apply it and ensure that soils are properly removed. Table 2 provides guidance on how one might select a cleaning compound based on the type of soil. When a chemical company formulates a cleaning compound, the following elements are considered:
- Bringing the cleaning solution into contact with the soil being removed.
- Displacing the soils from the surface being cleaned
- Dispersing the soil into the cleaning solution
- Preventing deposition of the soil back onto the clean surface
In addition, cleaning compounds should soften water, disperse or dissolve quickly and completely, and be non-toxic, non-corrosive and safe to handle and use at the recommended concentrations and temperatures.
One of the elements of TACT WINS is concentration. Note that when looking to clean sugars and starchy foods, the suggestion was to use a mild alkali. Stronger concentrations may be needed for different foods and processing systems. As an example, when cleaning deep-fat fryers, a strong alkaline or caustic product is usually used, thanks to polymer buildup on surfaces. The polymer forms as a result of the plating of oxidative and thermal polymers on the surface of the fryer.
When talking about cleaning and cleaning compounds, one must incorporate the “A for action” in TACT WINS into the equation. This is the physical force exerted on the surface to ensure that the soil is properly removed. Action can be the turbulent flow of cleaning compounds through a pipe or within a tank (CIP Systems); it can be the activity of foam cleaner on the surface; or the force applied through scrubbing a surface with brushes or scrub pads.
Cleaning using CIP systems is accomplished through the circulation of different solutions through the system and generally do not entail the removal of plumbing. The technology can be used in closed loop systems where the different fluids are recirculated or in single pass operations where CIP is used in combination with manual cleaning. Examples of closed loop systems are sanitary process lines such as those used in aseptic processing systems and vessels like blend tanks.
CIP systems have several distinct advantages. These include reduced labor costs, automation, the use of strong alkali cleaners, faster operation (TIME), fewer leaks and potential equipment damage from disassembly, recirculation of cleaners and more effective cleaning.
Today, almost all CIP systems are automated. There are tanks for cleaners and sanitizers and the metering pumps from drums or bins of chemicals which must be properly calibrated to ensure that the proper CONCENTRATION of cleaner is mixed with water, control panels and a means to document the cleaning process.
The CIP system will be linked to the processing equipment and used as needed, which would usually be at the end of a day’s production run or between products. The type of CIP system that a company would use depends upon the products being manufactured or the NATURE of the soil. Complex formulations such as puddings will require a more complex cleaning regimen, especially if they are being processed aseptically which means there will more burn-on on the SURFACE than a sugary drink.
There is an additional type of cleaning called COP, or Clean-out-of-Place. Many operations have installed COP tanks to clean small parts such as small equipment, short pipes, gaskets and clamps. These items from the equipment to be cleaned are completely disassembled and placed in baskets or perforated containers in a tank where cleaning compounds are circulated. The cleaned units may be sanitized using hot water or a sanitizing solution. But, there are companies that have installed large COP tanks to clean belts or conveyor systems. With these systems, the units being cleaned are moved to the tanks using fork lifts.
Sanitizers: Sanitizing is the treatment of a cleaned surface with a chemical or physical agent to destroy disease/spoilage-causing organisms. Sanitizing reduces the total vegetative cell population to a safe level. There are many different chemical sanitizers that are used in the food processing industry. These include the following:
- Chlorine gas
- Chlorine dioxide
- Formulated products (Combinations)
- Acid sanitizers
- Peracetic Acid
- Quaternary Ammonia Compounds
As noted earlier, heat (physical means) may also be used to sanitize surfaces. Recommended procedures for sanitizing with heat include exposure of a surface to hot water at a minimum of 180oF for five minutes or exposure of a surface to steam at minimum of 200oF for the same time period. By exposure, it means that the surface actually reaches those temperatures and is maintained at temperature for five minutes.
When selecting a sanitizer for use in a food processing operation, factors that need to be considered are toxicity, antimicrobial activity (preferably wide spectrum), compatibility with cleaners, non-corrosive to the surfaces being sanitized, measurable biocidal activity, and an ability to be rinsed from the surface, if that is required or desired. Many of the sanitizers used are not rinsed and referred to as “No rinse sanitizers.”
There is another consideration today, and that is the environmental impact. Processors are looking to utilize sanitizers that breakdown into safe end products or do not form potentially toxic materials. In addition, the surface to be sanitized needs to be considered. Is the sanitizer circulating through a CIP system or will it being applied to the surface of a cleaned piece of equipment? Not all of the sanitizers noted above are considered to be good hard surface sanitizers. Quaternary ammonia compounds (quats) are good hard surface sanitizers because they do not dissipate easily, whereas ozone dissipates rapidly and is, therefore, a poor choice for such an application. Peracetic acid, an excellent sanitizer in fluid system, also dissipates rapidly from surfaces and has a distinct and often irritating odor. It should be used in well-ventilated areas. Note that the list above includes formulated products. Chemical suppliers are now blending combinations of approved chemicals to meet specific sanitizing needs.
Educating the workforce
It is imperative that the processor develop detailed procedures for outlining all cleaning operations. Note that it is the processor’s responsibility to develop the procedures. There once was a time when the suppliers of cleaning chemicals would develop these procedures for processors, but that has changed.
The chemical suppliers are concerned about liability, so they no longer offer this service beyond offering advice. The mantra, however, is develop, document, implement and maintain. These procedures should be clearly written, define the ranges for chemical concentrates, temperatures of application and contact times. These protocols must also clearly elucidate the personal protective equipment (PPE) that each individual doing the work shall wear.
To further emphasize the importance of the PPE, icons depicting the required PPE should be included in the written procedures. An integral part of implementation is education and training. To meet this mandate, management must take the time to properly educate all persons assigned to the cleanup crew using the documented procedures as a basis for the educational process. In addition, the educational process must address safe handling of all chemicals. Lastly, it is imperative that these educational sessions be documented for all persons who receive the training. Proper documentation of such sessions ensures that people are not only properly educated but can minimize potential liability if there is an accident.
The last of the Principles of Sanitary Design is that the cleaning and sanitizing programs used for equipment should be validated. This is a common-sense practice that each and every processor should adopt for each piece of equipment. Interestingly, the Preventive Controls for Human Food Regulation found in 21 CFR Part 117 does not mandate that sanitation preventive controls be validated. yet this is a requirement of the ISO 22000 system and several of the Global Food Safety Initiative (GFSI) audit schemes.
Validation entails developing a cleaning procedure and ensuring that it is effective using visibly clean criteria and quantifiable methods such as microbiological swabbing, ELISA tests for allergens, ATP bioluminescence or other methods. When validating a cleaning and sanitizing protocol, the procedure should be successfully completed at least twice. Some companies mandate that the tests should be repeated three times as part of the validation procedures.
If the target of the validation tests is for allergens, the validation trials should target the most prominent allergen if there are multiple allergens in the product. These testing protocols can be quite complicated especially if one is testing a filler for beverages. The recommendation is that each filler head be swabbed, so if a filler has 50 filler heads, one is looking at a lot of swabbing. And, once that procedure is properly validated it must be repeated day after day to ensure that the equipment is properly cleaned. The documented procedures for cleaning should also include routine verification activities ensure that the work has been done properly.
Developing, documenting, implementing and maintaining programs to ensure that equipment and the physical plant are properly cleaned is an essential element for ensuring food safety. In many processing operations, the cleaning protocols for some pieces of equipment are actually considered preventive controls or operational prerequisite programs within the food safety management system. To meet this goal, food processors must adhere to established protocols day after day and management must develop programs to verify that this has been done. And, remember, one cannot sanitize a dirty surface, so make sure that the cleaning programs are well-designed and followed to the letter.
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